U.S. patent application number 11/315651 was filed with the patent office on 2007-06-28 for concentrating catalytic hydrogen production system.
This patent application is currently assigned to United Technologies Corporation. Invention is credited to Rakesh Radhakrishnan, Joseph J. Sangiovanni, Thomas H. Vanderspurt.
Application Number | 20070148084 11/315651 |
Document ID | / |
Family ID | 38194000 |
Filed Date | 2007-06-28 |
United States Patent
Application |
20070148084 |
Kind Code |
A1 |
Radhakrishnan; Rakesh ; et
al. |
June 28, 2007 |
Concentrating catalytic hydrogen production system
Abstract
A solar-powered hydrogen production system directly produces
hydrogen. The solar-powered hydrogen production system includes at
least one concentrator, a hydrogen-rich source, a catalytic layer,
and a hydrogen separation membrane. The hydrogen-rich source is
positioned to receive focused sunlight collected by the
concentrator and is in direct contact with the catalytic layer. The
catalytic layer produces hydrogen from the hydrogen-rich source.
The hydrogen separation membrane subsequently separates the
hydrogen produced at the catalytic layer.
Inventors: |
Radhakrishnan; Rakesh;
(Vernon, CT) ; Vanderspurt; Thomas H.;
(Glastonbury, CT) ; Sangiovanni; Joseph J.; (West
Suffield, CT) |
Correspondence
Address: |
KINNEY & LANGE, P.A.
THE KINNEY & LANGE BUILDING
312 SOUTH THIRD STREET
MINNEAPOLIS
MN
55415-1002
US
|
Assignee: |
United Technologies
Corporation
|
Family ID: |
38194000 |
Appl. No.: |
11/315651 |
Filed: |
December 22, 2005 |
Current U.S.
Class: |
423/648.1 ;
48/61 |
Current CPC
Class: |
C01B 2203/0495 20130101;
Y02E 60/36 20130101; C01B 2203/0405 20130101; B01J 2219/0877
20130101; C01B 3/042 20130101; C01B 13/0207 20130101; C01B 3/501
20130101; B01J 19/127 20130101; B01J 2219/0892 20130101; Y02P
20/133 20151101 |
Class at
Publication: |
423/648.1 ;
048/061 |
International
Class: |
C01B 3/02 20060101
C01B003/02 |
Claims
1. A solar-powered hydrogen production system, the system
comprising: at least one concentrator for collecting and focusing
sunlight; a hydrogen-rich source positioned to receive the sunlight
collected by the concentrator; a catalytic layer in direct contact
with the hydrogen-rich source for producing hydrogen; and a
hydrogen separation membrane for separating the hydrogen produced
at the catalytic layer.
2. The hydrogen production system of claim 1, and further
comprising a plurality of concentrators.
3. The hydrogen production system of claim 1, wherein the catalytic
layer comprises a photocatalyst.
4. The hydrogen production system of claim 1, wherein the catalytic
layer comprises a thermocatalyst.
5. The hydrogen production system of claim 1, wherein the catalytic
layer comprises a photoelectrochemical cell.
6. The hydrogen production system of claim 1, wherein the catalytic
layer comprises a photochemical cell.
7. The hydrogen production system of claim 1, wherein the hydrogen
separation membrane separates the hydrogen from secondary
components in the hydrogen-rich source.
8. A concentrated solar catalytic hydrogen production system for
direct production of hydrogen from a hydrogen-rich source, the
system comprising: at least one optical element for concentrating
sunlight; a catalytic cell positioned to receive concentrated
sunlight from the optic lens; and a hydrogen separation device for
separating hydrogen from secondary components produced in the
catalytic cell.
9. The hydrogen production system of claim 8, wherein the optical
element is a concentrator for focusing sunlight into a high density
energy beam.
10. The hydrogen production system of claim 8, and further
comprising a plurality of optical elements.
11. The hydrogen production system of claim 8, wherein the
catalytic cell comprises a photocatalyst, a thermocatalyst, or a
combination thereof.
12. The hydrogen production system of claim 8, wherein the
catalytic cell comprises a photoelectrochemical cell.
13. The hydrogen production system of claim 8, wherein the
catalytic cell comprises a photochemical cell.
14. The hydrogen production system of claim 8, wherein the hydrogen
separation device is a hydrogen separation membrane.
15. A method for directly producing hydrogen using solar energy,
the method comprising: capturing sunlight with a plurality of
concentrators; directing the captured sunlight to a catalytic layer
and through a hydrogen source to produce hydrogen and secondary
components; and separating the hydrogen from the secondary
components.
16. The method of claim 15, wherein capturing sunlight with a
plurality of concentrators comprises using concentrators having
non-imaging optics.
17. The method of claim 15, wherein directing the captured sunlight
comprises focusing a high energy density beam onto the catalyic
layer.
18. The method of claim 15, wherein the catalytic layer is a
photoelectrochemical cell or a photochemical cell.
19. The method of claim 15, wherein the catalytic layer comprises a
photocatalyst, a thermocatalyst, or a combination thereof.
20. The method of claim 15, wherein separating the hydrogen from
the secondary components comprises using a hydrogen separation
membrane.
Description
BACKGROUND OF THE INVENTION
[0001] Photochemical and photoelectrochemical cells have the
ability to extract energy from sunlight. This solar energy can be
used for direct hydrogen production upon converting the solar
energy into chemical energy by exciting atoms or molecules and
making them more reactive, typically by producing free radicals.
Made up of a semiconducting electrode (or photoanode) and a metal
cathode immersed in an electrolyte, when light hits the cell, a
portion of the light falling within a specified range of the
electromagnetic spectrum is absorbed into the semiconductor
material so that the energy of the light is transferred to the
semiconductor. Upon absorption of the light, the cell generates
energy, which is then used for the electrolysis of water, or other
hydrogen-rich source. In the example of water, the water is
oxidized by reacting with free holes (2h.sup.+) at the electrode to
produce hydrogen (H.sup.+) ions and oxygen, as shown by the
following reaction:
2h.sup.++H.sub.2O=1/2O.sub.2(gas)+2H.sup.+.sub.(aq) The H.sup.+
ions are then reduced to hydrogen by electrons at the cathode to
produce hydrogen, as shown by the following reaction:
2e.sup.-+2H.sup.+.sub.(aq)=H.sub.2(gas)
[0002] Current state of the art photoelectrochemical and
photochemical systems are less than 10 percent efficient in
producing hydrogen from absorbed light. A photoelectrochemical or
photochemical system that can increase the hydrogen production
conversion efficiency rate to approximately 30% would be a viable
and cost effective alternative to current hydrocarbon fuel
processing systems that emit green house gases during hydrogen
production. Because solar cells can produce usable energy using a
non-polluting renewable energy resource, photoelectrochemical and
photochemical cell systems have become a focus in the area of
hydrogen production.
BRIEF SUMMARY OF THE INVENTION
[0003] A solar-powered hydrogen production system directly produces
hydrogen. The solar-powered hydrogen production system includes at
least one concentrator, a hydrogen-rich source, a catalytic layer,
and a hydrogen separation membrane. The hydrogen-rich source is
positioned to receive focused sunlight collected by the
concentrator and is in direct contact with the catalytic layer. The
catalytic layer produces hydrogen from the hydrogen-rich source.
The hydrogen separation membrane subsequently separates the
hydrogen produced at the catalytic layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The figure is a schematic diagram of an embodiment of a
concentrating catalytic hydrogen production system having a
catalytic layer.
DETAILED DESCRIPTION
[0005] The sole figure represents a schematic diagram of
concentrating catalytic hydrogen production system 10 that includes
concentrators 12a, 12b, 12c, and 12d, catalytic layer 14,
hydrogen-rich layer 16, hydrogen separation membrane 18, and
hydrogen outlet 20. Hydrogen production system 10 uses solar energy
captured from concentrators 12a-12d to produce hydrogen.
Concentrators 12a-12d direct sunlight S to catalytic layer 14 which
produces hydrogen from hydrogen-rich layer 16. Hydrogen production
system 10 provides high hydrogen generation rates while being an
environmentally friendly alternative to fuel processing systems
that emit green house gases during the production of hydrogen.
[0006] In operation, concentrators 12a-12d are aligned normal to
the direction of incident sunlight in order to capture the maximum
amount of light rays from the sun. Concentrators 12a-12d are
typically positioned directly above catalytic layer 14 and have
non-imaging optics that focus a high energy density beam from
sunlight S collected through concentrators 12a-12d to catalytic
layer 14. The optical design of concentrators 12a-12d can be either
reflective or refractive optics that concentrate the solar energy
collected from the sunlight to achieve a concentration ratio of
between one sun and ten thousand suns. Additionally, concentrators
12a-12d may comprise optical filter materials to filter out
wavelengths based on the light absorption properties of catalytic
layer 16. Although the figure depicts hydrogen production system 10
with four concentrators 12a-12d, hydrogen production system 10 may
include as many concentrators as necessary to produce the desired
amount of hydrogen needed at a specific site.
[0007] The light collected by concentrators 12a-12d penetrate into
catalytic layer 14, which is in direct contact with hydrogen-rich
layer 16. Catalytic layer 14 can be a photocatalyst, a
thermocatalyst, or a combination of both that is comprised of a
multijunction photoelectrochemical or photochemical cell capable of
capturing and converting a broad range of wavelengths to electrical
or thermal energy, respectively. The solar energy collected in the
form of light and heat facilitates the photochemical and/or
thermochemical reactions, or a combination of both, necessary to
convert the components in hydrogen-rich layer 16 to hydrogen.
Hydrogen-rich layer 16 can be any source containing hydrogen, such
as water or fuel. The light absorption properties of catalytic
layer 14 can optionally be tuned or enhanced using organic dyes,
semiconductors, quantum dots, metal oxides, metals, and the like.
In one embodiment, catalytic layer 14 is titanium dioxide.
[0008] Once the components in hydrogen-rich layer 16 have been
reacted and the hydrogen has been split from the other secondary
components, hydrogen separation membrane 18 separates the hydrogen
from the secondary components. Hydrogen separation membrane 18 can
be formed of various membrane materials, including, but not limited
to: inorganic membranes, organic membranes, ceramic-based
membranes, silica-based membranes on ceramic or metal supports,
palladium membranes, or a membrane that is a binary, ternary, or
quaternary combination of palladium and other metals. After the
hydrogen has been separated from the secondary components from
hydrogen separation membrane 18, the hydrogen is transported by
hydrogen outlet 20 to an external source for use. For example, the
hydrogen can be sent to an engine or a fuel cell to generate
electricity.
[0009] The catalytic hydrogen production system is set up as a flow
system that produces hydrogen while simultaneously separating
hydrogen from secondary components using a hydrogen separation
membrane. The hydrogen production system generally includes a
plurality of portable concentrators that capture and focus a high
density energy beam of light to a catalytic layer, such as a
photoelectrochemical or photochemical cell, that is in direct
contact with a hydrogen-rich source. The catalytic layer splits the
hydrogen from secondary components in the hydrogen-rich source. A
hydrogen separation membrane then separates the hydrogen from the
secondary components for direct hydrogen production. The hydrogen
can subsequently be used as fuel.
[0010] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *